Microcard viewer



Feb. 1, 1955 E. o. PETERS ET AL 2,700,917

MICROCARD VIEWER Filed Sept. 15, 1951 v 2 Sheets-Sheet 1 Avg/5,

United States Patent MICROCARD VIEWER Edward 0. Peters and Adrian P. Brietzke, La Crosse, Wis., assignors to Northern Engraving & Manufacturing Co., La Crosse, Wis., a corporation of Wisconsin Application September 15, 1951, Serial No. 246,824

3 Claims. (Cl. 88-24) This invention relates to a microphotograph viewer, and more particularly to a microphotograph viewer wherein the card upon which the microphotographs are printed is adapted to be manually moved to select the desired microphotograph to be viewed.

Microphotographs of books and documents are now printed on cards, called microcards, which are adapted to be inserted in a machine called a microcard viewer, for reading the microphotographs thereon. In going from one page to another, which are photographed on the microcard, it is necessary to shift the microcard with respect to the microcard viewer.

During the shifting of the microcard, it is very important that the distance from the illuminated surface of the card to the focusing lens be kept constant, for if that distance varies, then the lens must be refocused. The smallest variation on this focus distance results in a fuzzy projection of the microphotograph and requires refocusing. Constant refocusing is very time consuming and consequently reduces the utility of the microcard system.

It is also important to keep the microcard from moving once it has been positioned, as a relatively small inadvertent displacement of the microcard may mean skipping a large number of microphotographs on the card.

Heretofore, microcards have been carried in frames or carriers which are provided with positive drive means, usually gears or the like, for the purposes of maintaining the microcard in position after it has been set, and also for use in shifting the card while trying to maintain the distance from the illuminated surface of the microcard to the lens constant. guides therefor, must be made very accurately, and accurately aligned with the axis of the lens, and the cost of such custom work on each carrier is very great.

There have been attempts to avoid the costly custom work on such carriers but these attempts still retain the concept of using a carrier for the microcard, and machine elements for the shifting of the microcard carrier.

Even the use of carefully constructed carriers and guides does not obviate the fact that the microcards themselves, when held in said carriers, may have portions of their surface which do not lie in a single plane. One reason may be that the card is slightly curved or warped, or the card may be of uneven thickness. In any event, this variation in the surface of the card manifests itself in the microphotographs being out of focus when the carrier is shifted, and results in requiring the observer to refocus the microcard viewer.

Thus, one of the objects of this invention is to provide a microcard viewer wherein the distance from the illuminated surface of the card to the focusing lens is maintained constant despite variations in the curvature of the micirocard or variations in the thickness of the microcar Another object of this invention is to provide a microcard viewer wherein the illuminated surface of the microcard is maintained at a constant distance from the focusing lens and wherein all frames, carriages, guides and the like, heretofore employed for that purpose, are eliminated.

A further object of this invention is to provide a microcard viewer wherein the illuminated surface of the microcard is maintained at a constant distance from the focusing lens and wherein the microcard is maintained in its position after it has been set, without employing frames, carriages, guides, and the like, which have heretofore been employed, for that purpose. 4

Still another object of this invention is to provide a These carriers or frames, and the r ice microcard viewer wherein the illuminated surface of the microcard is maintained at a constant distance from the focusing lens and wherein the microcard is adapted to be manually shifted from one position to the next.

Another undesirable feature of microcard viewers which have heretofore been made is that the microcard is positioned out of view of the observer when the ob server is facing the viewing screen. There have been previous attempts to make microcard viewers wherein the cards were manually manipulable to a desired position, but these machines have been unsatisfactory, in that the microcard was positioned out of view of the observer when the observer was facing the viewing screen. In the process of manually positioning the microcard, there is a definite advantage to the observers coordination if the observer can see his hands, the object being positioned, and the projected image simultaneously.

Thus, still a further object of this invention is to provide a microcard viewer wherein the microcard is adapted to be manually manipulated to desired positions and wherein the microcard and viewing screen may be simultaneously observed.

And still another object of this invention is to provide a microcard viewer which is characterized by its simplicity and inexpensiveness of construction and by its novel arrangement of elements whereby each of the objects hereinabove recited is attained.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is an isometric view of the microcard viewer;

Figure 2 is an enlarged side cross section view taken on a plane through the center of the microcard viewer;

Figure 3 is a view taken substantially on line 3-3 of Figure 2;

Figure 4 is a greatly enlarged view, partly in cross section, of the focusing lens sub-assembly and the contact glass, and showing a microcard held in position by the clamping member;

Figure 5 is an isometric view of the light source and light condenser sub-assembly;

Figure 6 is a view of portions of the sub-assembly shown in Figure 5 and is taken substantially on line 6-6 of Figure 2;

Figure 7 is another view of portions of the sub-assembly shown in Figure 5, and is taken substantially on line '77 of Figure 2.

Referring now to the figures, there is shown in Figure 1 a microcard viewer having a box-like casing, generally indicated at 10, supported on a stand 12. The casing 10 is composed of what may be considered to be two separate casings 14 and 16 which have a common dividing wall 18 therebetween. The lower casing 16 has mounted therein the light source and the light focusing and condensing means for projecting light onto the microcard, and the upper casing 14 is positioned to receive the reflected light from the microcard and to direct it onto a viewing screen which forms one wall of the upper casing 14. The upper casing is also provided with a handle 19 on the outside thereof, for the purpose of carrying the entire machine. A microcard supporting shelf 20 is attached to the lower casing 16, as shown in Figure l.

The light producing and condensing sub-assembly 22, shown per se in Figure 5 and also seen at Figures 2, 6, and 7, includes a bracket 24 which is adapted to be mounted in opposite upright Walls of the lower casing 16. The bracket 24 has slotted mounting holes 26 for adjustably positioning the bracket 24 within the lower casing 16.

Mounted on bracket 24 are a set of bayonet type electrical contacts 28 which are adapted to be connected to a source of power by means of an electrical cord 30. The bayonet contacts 23 are adapted to have a lamp 32, with appropriate mounting sockets 34 therein, in electrical contact therewith. The sockets 34 and the bayonets 28 are so arranged that the filaments 36 of the lamp 32 are aligned, as shown in Figures 2 and 5, to lie in a plane perpendicular to the direction in which the light is directed through the light condenser.

The remainder of the light producing and condensing sub-assembly 22 comprises a condenser, generally indicated at 38, and a reflector generally indicated at 40. The reflector 40 includes a concave mirror 42 mounted on a bracket 44. This bracket 44 is pivotally mounted on one wall of bracket 24 and is adapted for spacial adjustment with respect to lamp 32 by means of slot 45. This provides that the focal point of the mirror 42 may be variably spaced from the filaments 36 and also provides that the geometrical axis of the mirror 42 may be angularly ad usted with respect to the axis of the condenser 38. This permits the manipulation of mirror 42 so that the filaments 36 appear to be double in number, as shown in Figure 6, and so serve to distribute the intense illumination of the incandescent filaments 36 over a greater area of the condenser lens. The mirror 42 is simply positioned on bracket 44 by means of embossments 46 which engage the edge of mirror 42 and by means of leaf spring 48 which clamps the mirror 42 against bracket 44.

The condenser 38 is a two-lens condenser, and 50 is a heat absorbing glass. A spring 51 maintains the focusing lenses 50a and 50b in position in the condenser 38 in a well-known manner.

The condenser 38 is not adapted for spacial adjustment with respect to the lamp 32 and is fixed in position by means of bolts 52 and 53. The bolt 52 serves double duty in positioning the condenser 38 and in also serving as the mounting bolt for the reflector 40. The bolt 52 extending through slot 45 permits spacial and angular adjustment of the reflector 40 and also serves to clamp the condenser 38 and the reflector 40 in position on the bracket 24.

The condenser 38 is provided with air vents 54 and the lower casing 16 is also ventilated by air inlet louvers 56 and air outlet louvers 58. A tremendous amount of heat is generated by the lamp 32 and it is, therefore, important that sufficient ventilation be provided.

The extended end of condenser 38 passes through the lower wall 59 of lower casing 16 and is shaped to cooperate with a lens sub-assembly which is indicated at 60.

The lens sub-assembly 60 is located on the lower side of upper casing 14. This lens sub-assembly 60 includes a castin 62, a contact glass 64, a focusing lens generally indicated at 66, and a lateral aperture 67 adapted to be aligned with the exit end of the condenser 38.

The contact glass 64 is seated in casting 62 and is kept in position by retainer 68. The retainer 68 is secured to casting 62 by means of the single screw 70. The contact glass 64 has a tapered edge 72 with which the retainer 68 cooperates to clamp the contact glass in position in casting 62, and for another reason hereinafter described.

The focusing lens 66 is mounted in a bore 74 in casting 62 and is adapted to be moved toward and from contact glass 64 for the purposes of focusing. The focusing lens 66 and the contact glass 64 are coaxially positioned. Leaf sprin s 76 bias the focusing lens 66 toward the contact glass 64 and the bifurcated pivoting lever 78 is adapted to move the focusing lens 66 against the bias of springs 76 in the direction away from contact glass 64. The bifurcated pivoting lever 78 is actuated by a member 80 which is threaded in casting 62 and has a focusing knob 82 thereon for the purposes of manipulation.

As shown in Figure 2, the light that is reflected from the microcard C passes through the contact glass 64, then through focusing lens 66 onto mirror 84, thence onto mirror 86, and from there onto the projection or viewing screen, generally indicated at 88. The mirrors g4 and 86 are supported at their edges by rubber mounts Means are also provided for varying the angle between mirror 84 and mirror 86. This includes the threaded bolt 92, which also serves as a support for mirror 86, and the spring 94 concentric therewith. The bolt 92 is threaded to nut 96 which is fixed to the edge of mirror 86. The bolt 92 and the spring 94 cooperate to provide adiustment means for increasing or decreasing the angle between the mirrors. The bolt 92 has a slotted head, thus providing that adjustment of the angle between mirrors 84 and 86 may be made simply by use of a screw driver.

The projection or viewing screen 88 comprises an inner clear glass 93, a Fresnel middle lens 100, and an outer ground glass 102.

Referring back to the contact glass 64, the outer or contact face 104 of contact glass 64 is spaced from the microcard support shelf 20 a distance slightly greater than the thickness of the microcard C. This permits the insertion of a microcard C between shelf 20 and contact glass 64.

The shelf 20 has an aperture 106 therethrough located opposite the contact glass 64. A clamping member 108 is mounted on a leaf spring 110 and is adapted to be forced by spring 110 through aperture 106 toward the contact face 184 of contact glass 64. The leaf spring 110 is secured to the shelf 20 by means of rivet 111, as shown in Figure 2.

The clamping member 108 is loosely connected to spring 110 by means of rivet 112. This loose connection between clamping member 108 and spring 110 permits the full seating of clamping member 108 on the back side of microcard C, so that the spring force is distributed over the entire portion of card C in contact with the face 114 of clamping member 108.

The diameter of face 114 of clamping member 108 is greater than the diameter of face 104 of contact glass 64 so that the entire portion of the microcard C, which is in contact with face 104, is clamped thereagainst.

The spring 110 is also provided with a flange 116 adapted to be grasped by the thumb or finger of the operator to depress the spring 110 and to thereby depress clamping member 108 to permit insertion of the microcard C between the clamping member 108 and the contact glass 64.

The edge 118 of the clamping member 108 is tapered toward contact glass 64 so that when the edge of the microcard C is forced thereagainst it will serve to depress the clamping member 108, and thus this also provides means for insertion of the microcard C between clamping member 108 and the contact glass 64. The tapered edge 72 of the contact glass 64 cooperates, when the microcard C is thus inserted, so that the microcard C will not catch on the edge of the contact glass 64.

In the operation of the microcard viewer, the light directly from the filaments 36, and the light reflected from mirror 42, is directed through the condenser 38, through the lateral aperture 67 in the casting 62, through the contact glass 64, and onto the portion of the microcard C which is clamped against the contact glass 64. The light reflected from the microcard C passes through the contact glass 64, through the focusing lens 66, onto the mirror 84, thence to the mirror 86, and onto the viewing screen 88. By merely manipulating the focusing knob 82, the picture may be brought into focus. Thereafter any portion of the microcard which is in contact with the face 104 of contact glass 64 is at a fixed distance from the focus lens 66 and, therefore, refocusing of the machine is unnecessary.

A further desirable feature of the entire system is found in that if the microcard C were spaced from the contact glass 64 or from the lens 66, as is the practice in systems existing heretofore, there would be a certain amount of reflection from the surface of the microcard to the opposite face of the contact glass or lens and a portion of this light would be re-reflected onto the card, resulting in fuzziness of the characters printed thereon by reason of the multiple reflections. In the present system, it will be noted that when the microcard C is pressed flush against the face 104 of contact glass 64, such multiple reflections are obviated and the images receive only the direct light from the condenser and only the single reflection is transmitted through the contact glass 64 and through the focusing lens 66.

A further important feature is that the wall 120 of the lower casing 16, to which wall the microcard support shelf 20 is secured, is so positioned that a large recess 122 is provided behind the contact glass 64 to accommodate the positioning of large size microcards on the support shelf 20.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is: j

1. A microphotograph viewer comprising a casing, a screen upon which an enlarged picture is to be projected, a contact glass adapted to contact the surface of a microphotograph, means for directing light through the contact glass onto the microphotograph, means for focusing and directing reflected light from the microphotograph onto said screen, a microphotograph support shelf spaced from said contact glass, and means for maintaining the portion of the microphotograph being projected against said contact glass, said last means comprising an aperture in said shelf opposite said contact glass, a clamping member positioned opposite said contact glass, an elongated spring secured at one end thereof to said support shelf and resiliently biasing said clamping member through said aperture toward said contact glass, and a flange at the other end of said spring adapted to be grasped to aiford manual distortion of the spring, whereby the clamping member is displaced from said contact glass to permit insertion therebetween of a microphotograph.

2. A microphotograph viewer comprising a frame, a source of light positioned to illuminate a portion of a microphotograph to be viewed, a lens supported by said frame for focusing the light reflected from the microphotograph, a screen upon which an illuminated portion of a microphotograph is to be projected, and a holder for positioning the portion of the microphotograph to be projected at a predetermined attitude transverse to the optical axis of the lens, said holder comprising portions of said frame terminating at planes spaced from each other to define a slot into which a microphotograph may be introduced edgewise, the width of said slot being greater than the thickness of the microphotograph, a transparent contact member carried by said frame and having a contact surface thereon adapted to have the microphotograph pressed thereagainst, said contact member extending into said slot from one side thereof to position said contact surface in spaced relation between the planes of said terminal portions of the frame which define the sides of said slot, the spacing of said contact surface from the plane of the opposed terminal portion of said frame being greater than the thickness of the microphotograph, the portion of the frame opposite the contact surface of said contact member having an aperture therein, a clamping member movable through said aperture toward and away from said contact member, means resiliently biasing said clamping member through said aperture toward said contact member, and the edges of said clamping member and of said contact member being tapered in the directions toward each other, so that when the edge of a microphotograph is forced thereagainst, the clamping member will be displaced from the contact member to permit insertion therebetween of the microphotograph.

3. A holder for use with a viewer for microphotographs', which viewer includes a source of light for illuminating a portion of the microphotograph to be viewed, a lens for focusing the light reflected from the microphotograph and a screen upon which an illuminated portion of the microphotograph is to be projected; said holder comprising a frame carrying said lens, said frame having portions thereof terminating at planes spaced from each other to define a slot into which a microphotograph may be introduced edgewise to lie in a plane at a predetermined attitude transverse to the optical axis of the lens, the width of said siot being greater than the thickness of a microphotograph, a transparent contact member carried by said frame and having a contact surface thereon adapted to have a microphotograph pressed thereagainst, said contact member extending into said slot from one side thereof to position said contact surface in spaced relation between the planes of said terminal portions of the frame which define the sides of said slot, the spacing of said contact surface from the plane of the opposed terminal portion of said frame being greater than the thickness of a microphotograph, the portion of the frame opposite the contact surface of said contact member having an aperture therein, a clamping member movable through said aperture toward and away from said contact member, means resiliently biasing said clamping member through said aperture toward said contact member, and the edges of said clamping member and of said contact member being tapered in the directions toward each other, so that when the edge of a microphotograph is forced thereagainst, the clamping member will be displaced from the contact member to permit insertion therebetween of the microphotograph.

References Cited in the file of this patent UNITED STATES PATENTS 2,449,112 Frost Sept. 14, 1948 2,495,112 Wolff Jan. 17, 1950 2,495,528 Langan Jan. 24, 1950 2,501,453 Rowe Mar. 21, 1950 FOREIGN PATENTS 445,802 Germany June 18, 1927 295,703 Italy Apr. 28, 1932 

